| 摘要 |
<P>PROBLEM TO BE SOLVED: To restrain variations of storage states of variable resistant elements and enable high-performance memory operations, in a nonvolatile semiconductor storage device equipped with a memory cell array in which a plurality of memory cells having variable resistance elements which store information by the change of electric resistance caused by electric stress are arrayed in a line direction and in a row direction, respectively. <P>SOLUTION: A variable resistance element has resistance variation characteristics that the absolute value of a variation rate per time of a resistance value has a maximum value to the increase of an integrated impressing period and is below a prescribed value after passing the maximum value in an area in which a resistance value monotonously changes to the increase of the integrated impression period of electric stress. An information writing operation to a selected memory cell is conducted at the area as a writing state that the resistance value of the variable resistance element is within a first area R1, which is included in a resistance value range in which the absolute value of a variation rate of a resistance value is below a prescribe value after passing the maximum value. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
